Bacteriostats like 2,4,4'-trichloro-2'-hydroxydiphenyl ether are known deodorizers, and as such are used in deodorants, deodorant soaps, fabric sanitizers, and the like. Levels typically range from about 0.5% to about 5%. Furia et al., Soap & Chemical Specialties, January 1968, report that 20 ppm of the above compound on a diaper soiled with urine significantly reduced total microflora and total ammonia producing organisms in an overnight test. About 100 ppm reportedly reduced the viable cell counts by 90%. Although these data indicate that the compound is very effective, they do not suggest that it could be used in an animal litter product and be effective over a period of several weeks in eliminating ammonia and mercaptan odor.
Prior art attempts to deodorize cat litter include the addition of a perfume (see, e.g., U.S. Pat. No. 3,921,581, issued Nov. 25, 1975 to Brewer), and the addition of chlorophyll, mainly in the form of dried alfalfa to the litter (see, e.g., U.S. Pat. No. 3,923,005, issued Dec. 2, 1975 to Fry et al., assigned to The Clorox Company).
U.S. Pat. No. 4,129,094, issued Dec. 12, 1978 to Stockel, discloses the use of fly ash, bottom ash and/or boiler slag as cat litter materials. The composition of fly ash, as determined by the ASTM and cited in the patent, includes silicon dioxide, alumina, ferric oxide, calcium oxide, magnesium oxide, sodium oxide and potassium oxide.